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Materials and Modelling for Extreme Loading Conditions

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Materials Simulation and Design".

Deadline for manuscript submissions: closed (15 October 2021) | Viewed by 13168

Special Issue Editor


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Guest Editor
Politecnico di Milano, Department of Mechanical Engineering, via la Masa, 1, 20156 Milan, Italy
Interests: damage; impact; metal; ceramic; composite; simulations; experimental tests
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Investigation into the mechanical behavior of materials is a present challenge, especially if exploited in the building of predictive models aimed to replicate the mechanical behavior of complex systems and structures. Modelling approaches, validated by experimental tests, may allow for a better understanding of the physical phenomena involved, including more in deep knowledge about the mechanical behavior of the involved materials. Such modelling approaches can be considered as “virtual tests” intended to mimic, in an extremely realistic fashion, the behavior of materials and structures. Potentially, such kinds of approaches allow for performing optimization and fitness for purpose design, but also a safe, feasible, and effective approach to extreme loading conditions. Extreme loading conditions include unforeseen events, conditions that far exceed its original design, or very demanding requirements that are not included in the standard approaches. Catastrophic consequences may occur with some of these loading conditions, involving the loss of human lives.

Material behavior and modeling strategies aimed at investigating extreme loading conditions are very real and complex tasks. However, within the last few decades, key innovations have been achieved in both the field of a better understanding of the mechanical behavior of materials under extreme conditions, and in the field of creating a predictive modelling environment able to exploit these advances in the modeling of actual critical structures. Finally, increasing interest in such investigations has been shows by scientists and engineers, in both the theoretical and applicative fields.

This Special Issue aims to address the mechanical behavior of different kind of materials (metals, ceramic, composites, etc.) including innovative ones with focus on modelling approaches for extreme loading conditions: large deformation and failure, ballistic and low velocity impact, explosion, crack and damage, delamination, corrosion, and so on.

Papers dealing with the modeling of the mechanical behavior of materials, advanced simulation methods including both analytical and numerical approaches, multi-physics and multiscale approaches, testing solutions, and advanced applications to systems and structures and theoretical approaches, all in the field of extreme loading conditions, are encouraged.

Prof. Dr. Andrea Manes
Guest Editor

Manuscript Submission Information

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Keywords

  • extreme loading
  • material behavior
  • tests
  • simulations

Published Papers (5 papers)

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Research

19 pages, 4094 KiB  
Article
Numerical Simulations of Laser-Induced Shock Experiments on Graphite
by Alberto Morena and Lorenzo Peroni
Materials 2021, 14(22), 7079; https://doi.org/10.3390/ma14227079 - 22 Nov 2021
Cited by 2 | Viewed by 2068
Abstract
The development of particle accelerators with ever increasing energies is raising the standards of the structures which could interact with the particle beams. These structures could be subjected to strong shockwaves in accidental scenarios. In order to test materials in such conditions, one [...] Read more.
The development of particle accelerators with ever increasing energies is raising the standards of the structures which could interact with the particle beams. These structures could be subjected to strong shockwaves in accidental scenarios. In order to test materials in such conditions, one of the most promising techniques is the impact with high-power lasers. In view of the setting up of future experimental campaigns within the Petawatt High-Energy Laser for Heavy Ion Experiments (PHELIX), the present work aims at the development of a numerical approach for the simulation of graphite impacted by laser beams. In particular, the focus is on the spallation damage caused by shockwave reflection: a sufficiently intense laser beam could ablate the matter until plasma conditions, hence producing a shockwave which could travel inside the material and reach a free surface. A numerical model to properly describe the spall fragmentation of graphite has been calibrated on the basis of literature-available experimental data. The numerical approach is a ‘two-step’ procedure: the first step is the definition of the laser–matter interaction and the second one concerns the description of the shockwave evolution into matter. The simulations satisfactorily reproduce the dynamic response of graphite impacted by two different laser sources with various intensities, despite the difficulties of characterising a phenomenon which is extremely fast and chaotic. Full article
(This article belongs to the Special Issue Materials and Modelling for Extreme Loading Conditions)
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14 pages, 7494 KiB  
Article
Influence of Material Parameters on the Contact Pressure Characteristics of a Multi-Disc Clutch
by Yujian Liu, Man Chen, Liang Yu, Liang Wang and Yuqing Feng
Materials 2021, 14(21), 6391; https://doi.org/10.3390/ma14216391 - 25 Oct 2021
Cited by 4 | Viewed by 2173
Abstract
As an essential part of the transmission, the life of the clutch directly affects the stability of the transmission. In this paper, a finite element model and a thermodynamic numerical model of a multi-disc clutch are established to investigate the influence of material [...] Read more.
As an essential part of the transmission, the life of the clutch directly affects the stability of the transmission. In this paper, a finite element model and a thermodynamic numerical model of a multi-disc clutch are established to investigate the influence of material parameters on the contact pressure distribution. The pressure distribution index (PDI) is firstly proposed to evaluate the pressure difference among friction pairs. Moreover, the correctness of the numerical model is verified by the clutch static pressure experiment. The results show that increasing the elastic modulus and Poisson’s ratio of the backplate can effectively improve the uniformity of the contact pressure. However, the variations in material parameters of other clutch components can not easily smooth the pressure difference. Therefore, optimized material parameters for the clutch are proposed, where the maximum pressure and temperature differences are reduced by about 27.2% and 10.3%, respectively. Full article
(This article belongs to the Special Issue Materials and Modelling for Extreme Loading Conditions)
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19 pages, 5236 KiB  
Article
Experimental and Numerical Investigation on the Perforation Resistance of Double-Layered Metal Shield under High-Velocity Impact of Armor-Piercing Projectiles
by Riccardo Scazzosi, Marco Giglio and Andrea Manes
Materials 2021, 14(3), 626; https://doi.org/10.3390/ma14030626 - 29 Jan 2021
Cited by 12 | Viewed by 2936
Abstract
In the case of protection of transportation systems, the optimization of the shield is of practical interest to reduce the weight of such components and thus increase the payload or reduce the fuel consumption. As far as metal shields are concerned, some investigations [...] Read more.
In the case of protection of transportation systems, the optimization of the shield is of practical interest to reduce the weight of such components and thus increase the payload or reduce the fuel consumption. As far as metal shields are concerned, some investigations based on numerical simulations showed that a multi-layered configuration made of layers of different metals could be a promising solution to reduce the weight of the shield. However, only a few experimental studies on this subject are available. The aim of this study is therefore to discuss whether or not a monolithic shield can be substituted by a double-layered configuration manufactured from two different metals and if such a configuration can guarantee the same perforation resistance at a lower weight. In order to answer this question, the performance of a ballistic shield constituted of a layer of high-strength steel and a layer of an aluminum alloy impacted by an armor piercing projectile was investigated in experimental tests. Furthermore, an axisymmetric finite element model was developed. The effect of the strain rate hardening parameter C and the thermal softening parameter m of the Johnson–Cook constitutive model was investigated. The numerical model was used to understand the perforation process and the energy dissipation mechanism inside the target. It was found that if the high-strength steel plate is used as a front layer, the specific ballistic energy increases by 54% with respect to the monolithic high-strength steel plate. On the other hand, the specific ballistic energy decreases if the aluminum plate is used as the front layer. Full article
(This article belongs to the Special Issue Materials and Modelling for Extreme Loading Conditions)
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16 pages, 3617 KiB  
Article
Multiple Pseudo-Plastic Appearance of the Dynamic Fracture in Quasi-Brittle Materials
by Gianmario Riganti and Ezio Cadoni
Materials 2020, 13(21), 4976; https://doi.org/10.3390/ma13214976 - 5 Nov 2020
Cited by 3 | Viewed by 1598
Abstract
Understanding and simulating the dynamic response of quasi-brittle materials still remains as one of the most challenging issues in structural engineering. This paper presents the damage propagation material model (DAMP) developed in order to obtain reliable results for use in structural engineering practice. [...] Read more.
Understanding and simulating the dynamic response of quasi-brittle materials still remains as one of the most challenging issues in structural engineering. This paper presents the damage propagation material model (DAMP) developed in order to obtain reliable results for use in structural engineering practice. A brief overview focuses on the differences between fracture mechanics studies, and engineering material modelling is presented to highlight possible guideline improvements. An experimental dynamic test performed on ultra-high-performance concrete specimens was used to obtain evidence of the physical behaviour of brittle materials with respect to specimen size variations and, consequently, to verify the reliability of the material equations proposed. Two widely used material models (RHT and M72R3), as representatives of the classical brittle material models for structural purposes, and the proposed material model are compared. Here, we show how: (i) the multiple structural strength of brittle materials arises from the damage propagation process, (ii) there is no contradiction between fracture mechanics and the engineering approach once the velocity of damage propagation is chosen as fundamental material property and (iii) classical dynamic material models are intrinsically not objective with related loss of predictive capability. Finally, the original material model equation and the experimental strategy, dedicated to its extended verification, will be shown in order to increase the design predictiveness in the dynamic range considering structure and specimen size variations. The dynamic stress increasing factor (DIF), experimentally observed and widely recognised in literature as a fundamental concept for quasi-brittle material modelling, has been reviewed and decomposed in its geometrical and material dependencies. The new material model defines its DIF starting from the physical quantities of the damage propagation velocity applied to the test case boundary conditions. The resultant material model predictiveness results improved greatly, demonstrating its ability to model several dynamic events considering size and dynamic load variations with a unique material property set without showing contradictions between numerical and experimental approaches. Full article
(This article belongs to the Special Issue Materials and Modelling for Extreme Loading Conditions)
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21 pages, 24087 KiB  
Article
Improving the Blast Resistance of Large Steel Gates—Numerical Study
by Hasan Al-Rifaie and Wojciech Sumelka
Materials 2020, 13(9), 2121; https://doi.org/10.3390/ma13092121 - 3 May 2020
Cited by 18 | Viewed by 3340
Abstract
Blast resistant gates/doors are essential for sensitive infrastructure, such as embassies, ministries, or parliaments. Lightweight gates equipped with ‘energy absorbing systems’ have better operational performance than the traditional costly and bulky design. Graded auxetic structures have not yet been used as potential passive [...] Read more.
Blast resistant gates/doors are essential for sensitive infrastructure, such as embassies, ministries, or parliaments. Lightweight gates equipped with ‘energy absorbing systems’ have better operational performance than the traditional costly and bulky design. Graded auxetic structures have not yet been used as potential passive damping systems in the supporting frame of blast resistant gates. Consequently, this study tries to test if a uniaxial graded auxetic damper (UGAD) proposed by the authors in a recent article, namely the development of a new shock absorbing UGAD, could maintain a 3000 mm × 4500 mm steel gate operable after high blast peak reflected overpressure of 6.6 MPa, from 100 kg TNT at 5 m stand-off distance. The blast-induced response of the gate was assessed, with and without the proposed UGAD, using Abaqus/Explicit solver. Results showed that the attachment of the proposed UGAD to the gate led to a dramatic decrease in permanent deformations (a critical factor for gate operability after a blast event). Hence, a lighter, more economical gate (with 50% reduction in mass) was required to satisfy the operability condition. In addition, 49% of peak reaction forces were diminished, that have a direct impact on the supporting frame. Moreover, the results revealed that, in the numerical model, 56% of the achieved plastic dissipation energy was from the UGADs, and 44% from the gate. The outcomes of this research may have a positive impact on other sectors beyond academia, such as industry, economy, and public safety. Full article
(This article belongs to the Special Issue Materials and Modelling for Extreme Loading Conditions)
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